1. Field of the Invention
The present invention relates to a device and a method for rapidly lysing cells or viruses, and in particular, to a cell lysis device for lysing cells or viruses, which comprises a cell lysis tube having a sample inlet; a pump connected to the cell lysis tube for transferring a sample inside the tube; a sealing unit for temporarily sealing a specific region of the cell lysis tube; and a laser source for generating a laser, and a method of rapidly lysing cells or viruses using the cell lysis device.
2. Description of the Related Art
Efficient extraction of DNA from cells is needed in a variety of applications, and inter alia, such extraction of DNA is essential in molecular diagnosis, particularly identification and quantification of pathogenic bacteria. Molecular diagnosis is generally performed by DNA extraction followed by DNA amplification. Exemplary methods for DNA amplification include polymerase chain reaction (PCR), ligase chain reaction, stranded-displacement amplification, nucleic acid-based amplification, repair chain reaction, helicase chain reaction, QB replicase amplification, and ligation activated transcription.
Extraction of DNA from cells has been performed using materials, which have a tendency for DNA binding. Examples of the material used for DNA isolation include silica, glass fiber, anion exchange resins and magnetic beads (Rudi, K. et al., Biotechniques, 22, 506-511 (1997); and Deggerdal, A. et al., Biotechniques, 22, 554-557 (1997)). For the purpose of avoiding manual operation and eliminating operator errors, several automated machines have been developed for high-throughput DNA extraction.
Cell lysis is conventionally performed using mechanical, chemical, thermal, electrical, ultrasonic and microwave methods (Michael T. Taylor et al., Anal. Chem., 73, 492-496 (2001)).
Chemical methods for cell lysis involve the use of a lysing agent for disrupting cells and releasing DNA. Further, additional treatment of cell extract is required using a chaotropic reagent to denature proteins in the cell extract. One disadvantage with the chemical methods for cell lysis is that harsh chemicals are used to disrupt cells. Such chemicals may impede a PCR reaction that is performed using the cell extract after the cell lysis, and thus, purification of the DNA from the cell extract is necessary before performing the PCR reaction. Furthermore, chemical methods for cell lysis are labor-intensive, time-consuming and costly, and often produce low DNA recovery yields.
Thermal methods for cell lysis involve repeated freeze-thaw cycles. One disadvantage with the thermal method is that the method is often unable to disrupt many intracellular structures. Heating is an alternative method of disrupting the cell walls or cell membranes. One disadvantage with such a method is that heating causes denaturation of proteins, which may adhere to the released DNA, and thereby hinder DNA amplification.
The ultrasonic method is an alternative physical method for disrupting cells and releasing DNA. For the ultrasonic method, a cell solution or a cell suspension is placed in the chamber of an ultrasonic water bath. Ultrasonic cell destruction is highly ineffective in cell lysis. First, the energy distribution of an ultrasound is not uniform, and such non-uniform distribution of ultrasonic energy induces results that lack consistency. Further, the ultrasonic water bath is incapable of concentrating the ultrasonic energy into the cell solution container, and it usually takes several minutes to achieve complete disruption of the cells. Finally, ultrasonic cell destruction produces a sound that is unpleasant to human ears.
An alternative method for disrupting cells and releasing DNA employs a laser. An existing method for cell lysis using a laser is problematic in that irradiation of the cell solution with the laser causes an increase in the vapor pressure of the cell solution, and results in loss of the cell solution due to evaporation. The existing method employs a process of sealing the cell solution container with optic tape to prevent the loss of the cell solution by evaporation, but this taping process requires manual adhesion and removal of the tape.